Reinforced concrete step.



EATENTED 00T. 8, 1907.

G. M GRAHAM. -EEINEOECED CONCRETE STEP.

'APPLIGATION FILED JUNEl, 1807.

on. line :1f-x Fig. ly

' cross rail 2, consists ofv an outer tube 5,

UNiTED lSTATES PATENT OFFICE.

GEORGE M. GRAHAM, or CHICAGO, I LLiNO'Is, .--ASSIGNOR To G. A. EDWARD KonLEn, or.

- CHICAGO, ILLINOIS.-

`REINFORCED CONCRETE STEP.

Specification of Letters Patent# ratentsoct. 8,1907.

Application iilefi June 1,1 9072 Serial No. 376,869.

fication'. Th is invention relates to reinirced concrete'steps' for buildings, and has'for its objectlto provide a simplel and eiii'cieir't structural 'arrangement and combinations of parts whereby a .very strong andeconolxiicai step struc-' ture' is provided, alilas will hereinafter moreffully appear. In tile accompanying drawings j.-'T1f` igure 1, is a vertical 4section o fa portion of ja iiightof stairs'embodying the present invention. Fig.l 2, is afragnientry plan'v-iewof one side of the metal 'reinforcefrarne upon which the 'concrete-,massisLsupported.vl 3, .is a'detail section Similar numerals v.oft reference indicate like parts in the difierent'views; I I

Referring to the drawings', l1represents,the side' stringere o f the stairway-,which inthe present 'invention are preferably formed offsitructural metal suc'h as'chan- .nel bars, and havingthe usual'inclined arrangement, as shown.. v l

. I.2 are avserie's 'of ment, witheach cross rail in a vertical land ja horizontal piane, respectively,with the next adjacent'jcrossrails, as illustrated in FigJ-l'.

i 3, are windings oi wire Wound in the ci'rcil-it'ousman-4 ner show around the cross' rail s 2, so'as to form skeleton v supports for, the mass-of eo n c1 e te 4,wl`1ich whenl applied thereto forms the treads and risers of the stairsasshown,

and adapted-to afford' a fire proof structure of great In the preferred forni of the present invention, 'eachj ing said rails, and :and: windingsto form .thetreads and 'risers of the steps,"

and an inner. tube 6, with the'outer tube having abutment against the inner faces of the stringere 1,whil e the respective ends of the inner tube. passthrough orifices formed therefor in lthestrin'gersl land' are upset against the outer faces of .such strin'gers,4 as shown in'Fig. 3, to afoi'd'a very strong .and durable connection of the parts. Having thus fully'described my said invention, what Iclaim as new and desire to secure by Letters Patent,` y

1. Reinforced concrete stops.. comprising side stringers, 'a series of cross rails extending-between said stringers Vand arranged in zig-zag relation, ,windings of wire-connect'- a mass 'of concrete inclosng said rails substantially as set forth.

2. Reinforced concretesteps, comprising .side'stringf ers, a series of cross rails formed. of round tubing and ex- -tending between said stringers and arranged in zig-zagrelation, windings of wire connecting said rails and a mass of concrete inclosing'sad .rails and windings to yforni the treadsiand risers of the steps, substantiallyas set forth.

l `3.1 Reniorced concrete steps, comprising side stringers, al series ot' 4cross rails formed of `round.tubing'anden'- 'tending betwe'en Saidstringersand 'arranged in zig-zag re lation,l members arranged'-within said tubularcrss rails and extending through thestrlngers andupset against the V'outer facesthereof, windings fof 'wire connectingsaid rails, and a mass of concrete inclsixig said rails and'windings -tojformithe treads and risers of the steps, substantially as .f f set forth. round cross rails extendlngbetween the stringere 1 aforesaid', and hav-ing azig-zaglarrange.

I Reinfbi'ced`- concrtel steps; comprising side' stringers, a"serles of cross rails forme-dof round tubing `and-ex tending between. said Stringer-sand arranged in' zig-zag rc-y lat'ion, tubular members arranged within said tubular cross rails and extendingthrough the 4stringersand upset against the outer -i'as thereof, windings vof wire connecting said' rails, and a mass of'concrete'inclosingv said r'ails and windings to form the treads and risers of the steps, substanl tially as set forth..

Signed at Chicago, lllinois this723rd. day of May 1907. GEORGEM1 GRAHAM. witnessesz.

Ronna'r Bonus, FRANK S. Rnlp. 

